31: Congenital toxoplasmosis prevention by pyrimethamine-sulfadiazine vs spiramycin, a randomized trial

Abstract

To compare the efficacy and tolerance of prenatal treatment with pyrimethamine-sulfadiazine (PS) vs spiramycin (S) following primary maternal Toxoplasma gondii infection, to reduce perinatal transmission. A randomized, open-label trial in 36 centers in France, compared pyrimethamine (50 mg qd) + sulfadiazine (1g tid), with folinic acid vs spiramycin (1g tid). Pregnant women with confirmed seroconversion were eligible for the trial, after 14 weeks gestation. There was no change in usual procedures for serological screening, prenatal diagnosis or management of infected fetuses and neonates. 143 women were randomized from 11/2010 to 01/2014, 73 to PS and 70 to S. Baseline characteristics were well balanced between the 2 groups with a median age of 30 years (IQR 26; 32), a gestational age at seroconversion of 19 weeks (14; 25). An amniocentesis was performed in 132 cases, with a positive PCR for T. gondii in 7/68 (10.3%) in the PS group vs. 13/64 (20.3%) in the S group. Two pregnancies were terminated for fetal toxoplasmosis with cerebral abnormalities. Children with undefined infection status were excluded from primary analyses (N=18). The transmission rate was 12/65 in the PS group (18.5%), vs 18/60 in the S group (30%): OR = 0.53 (95% CI 0.23-1.22, p=0.15). The prenatal treatment effect was similar (OR=0.47; CI 0.18; 1.23; p=0.12) after adjustment for gestational week at seroconversion (OR=1.18 per additional week, CI=1.08-1.28 ; p<10-3) but tended to be stronger when started within 3 weeks of seroconversion (p=0.08 for interaction). Three SAE were possibly related to the study drugs, 2 toxidermias and one liver enzyme elevation, all in the PS group. This is the first RCT to study prenatal prophylaxis to prevent congenital toxoplasmosis. There is a trend towards lower transmission with PS, but it did not reach statistical significance, possibly due to lack of power because of premature termination of enrollment. This encourages further research to determine the efficacy of chemoprophylaxis following maternal primary toxoplasmosis.